The present invention relates generally to manufacturing processes. More particularly, the present invention relates to automatic detection of defects and generation of machine control code to facilitate defect repair.
During manufacturing assembly of products, many opportunities exist for creation of defects. Defects may be in the form of misplaced components, faulty or incomplete connections or out of specification electrical or mechanical features.
Implementation of a machine vision system allows monitoring, isolation and correction of defects before shipping products. Currently, a vision system identifies defects and prompts an operator to either pass the product to the next process or stop the assembly line and correct the defect. The first of these two alternatives is preferred because the assembly line operates at pulse rates far exceeding the typical repair time.
However, the passing of defective products affects downstream processes of the assembly line. Rework and repair are required. In one example, components are placed on a printed wiring board (PWB) in several steps. All components are then reflow soldered to the PWB in a single step. If the detected defect is located under a component placed during a subsequent step, the component must be removed to permit removal and repair of the defect. The removal of a subsequently placed part requires application of a large amount of heat to the PWB. This heat creates potential reliability problems for nearby components. Removal and replacement of components other than just the defective component greatly adds to the repair time and cost and introduces the possibility of additional defects.
Accordingly, there is a need for an improved method and apparatus for automatic defect detection and location, along with automatic suspension of placement of additional components in the vicinity of the defect.